This invention relates to improvements in fuse holders and more particularly to improvements in holders for indicating fuses.
An indicating fuse is used in an electrical circuit in which it is desirable to not only protect the circuit, but also, provide an indication of when the fuse has cleared or opened. An indicating fuse is releasably retained in an associated holder, such that an open fuse may be conveniently withdrawn from the holder, and a replacement fuse may be inserted in the holder. Electrical contact between the opposite sides of the indicating fuse and the confronting surfaces of the walls of the holder are made with insertion of the fuse into the holder.
Such an indicating fuse and its associated holder are shown and described in U.S. Pat. No. 3,190,987 to A. F. Fister, assigned to the assignee of the present invention. The fuse disclosed therein has generally rectangular terminals, which are contacted by the confronting convex wall surfaces of a generally U-shaped holder. This holder configuration provides two points of contact, one on each side for retaining the fuse. Experience has shown, however, that the two-point contact for retaining the fuse, suffers from difficulty in controlling the contact fit, between the fuse and the folder. Furthermore, repeated insertion and removal off the fuse, causes wear and deformation of the holder, resulting in loose contacts between the fuse and holder. This can result in decreased conductivity and increased heat build-up at the points of contact. In addition, retention of the fuse under conditions of vibration or mechanical shock is difficult to maintain.